separating signal from noise

Archive for the ‘Philosophy’ Category

Robin Hanson on the Overcoming Bias blog links to Scott Aaronson’s review of The Singularity is Near by Ray Kurzweil (which I’ve read, and whom I watched deliver a speech at the first Singularity Summit).

There’s a lot I could say about that review, and I will, but right now I just want to point out one thing that Aaronson writes:

Secondly, there’s nothing bad about overcoming nature through technology. Humans have been in that business for at least 10,000 years. Now, it’s true that fanatical devotion to particular technologies—such as the internal combustion engine—might well cause the collapse of human civilization and the permanent degradation of life on Earth.

Aaronson understands something that I was arguing with transhumanists years ago. The future is not about seeding the oceans with nitrogen or spraying the atmosphere with carbon-fixing nanobots. Those programs treat the symptoms, not the disease. The future is about a world without carbon dioxide production to begin with. It is a world without fossil fuels.

The combustion of reduced hydrocarbons is 1830s technology — it goes all the way back to whale oil, and we all know how good that was for whales. It’s time to make a fundamental shift in energy, and in that respect, our whole civilization. Clean, renewable energy is the way of the future, and transhumanists need to understand and promote it. Transhumanism must be a green philosophy.

When engaging believers, one is often confronted with the one of the following claims: “you have faith that the sun will rise tomorrow,” or “you have faith that your chair will hold you up when you sit on it.” The purpose of these kinds of accusations is to equivocate between two levels of uncertainty, pulling them both under the umbrella of “faith,” and thus to open the skeptic to the possibility of accepting the superstitious claims of the believer. In order to explain why this tactic is wrongheaded at best, and downright disingenuous at worst, I should first explain a few things about probabilistic reasoning.

Our beliefs do not fall cleanly into a dichotomy of certainty. We are not either 0% certain or 100% certain of a proposition. The certainty of our beliefs distributes on a continuum from 0 to 100% (or 0 to 1, whichever scale you prefer). I may be only 60% certain of the directions to a certain pizza place, but if I consult a map, having gained more evidence, I can increase my certainty to perhaps 99%. That’s what evidence does: it increases or decreases your certainty in a proposition (falsifying evidence decreases it).

Now, I have lots of evidence that the sun will rise tomorrow. I’ve seen it rise over 10,000 times, and I understand the deterministic laws of physics. Very strong evidence exists that it will rise tomorrow. I can probably assign a 99.99999…% certainty to that belief.

On the other hand, I don’t a high degree of certainty that God exists. I haven’t seen any evidence to establish a belief in God. Without any evidence, our certainty in a proposition should be 50% — that is, the proposition is as likely as it is unlikely. And in the case of the Christian God, my certainty is actually less than 1%.

The believer takes any certainty less than 100% as “faith” and equates them. Since you’re not 100% sure the sun will rise tomorrow, and you’re not 100% sure that God exists, your beliefs (or lack thereof) are both based on faith and are equivalent. I think you can see now why this reasoning is erroneous. A certainty of 99.999% is not equivalent to a certainty of 70%, or 50%, or 10%, or less than 1%.

Now, I said that without any evidence one way or another, our certainty should be 50%, but that my certainty of the Christian God is less than 1%. How is this so? In order to explain that, let me use an example.

Let’s say we’re in a public square surrounded by many people. You pull a man out of the crowd and ask me if he is an insurance salesman. Let’s say that I already know insurance salesmen constitute 10% of the general public (yes, I know that number is inaccurate, but let it suffice for the example). I would then have to say that I’m only 10% sure that the man in question is an insurance salesman. I have no other information, and our certainty when randomly pulling someone off the street should reflect the background probability.

Let’s say that you further ask if I believe he is an insurance salesman and a father. I know that 60% of adult men are fathers. I would have to tell you that I’m only 6% sure that he’s an insurance salesman and a father (.10 x .60 = .06).

You see, every time you add another proposition, you have to multiply the probability of each proposition being true together, so the probability decreases. If you claim that a vague “god,” “prime mover,” or “universal energy” exists, without defining the concept any further, I can say I have 50% certainty in that claim. But if you start enumerating a set of characteristics for that God — without any other evidence — my certainty in that exact God decreases.

The Christian God is described in great detail in the Bible. How certain can I be of a God who created the universe is six “days,” who created two people named Adam and Eve, who sent a flood, who dispersed the people of the earth after an incident at the Tower of Babel, who made the Israelites his chosen people, who sent 10 plagues against the Egyptians, who gave Moses a set of 10 commandments inscribed on two tablets, who impregnated a virgin, who took the form of a demigod named Jesus, who walked on water, who fed a multitude with a loaf of bread, who died on a cross, who rose from the dead, who… Well, you get the picture.

With all those propositions about the Christian God, my certainty in that exact god is way, way less than one percent.

Which is a lot less than 99.9999…% — my certainty that the sun will rise tomorrow.

So yes, I’m not 100% certain that the sun will rise. QM theory tells me that there’s something like a 1 in 10^500 chance that all the particles in the sun will vanish overnight. So at best my certainty in the sun rising is only 99.999…% taken to 499 decimal places. But that’s a lot more than my certainty in the Christian God, and they are not equivalent.

The most common argument for the existence of God these days seems to be the Argument from Design. Other arguments have come and gone, but the Design Argument remains popular. I want to finally put this argument to rest.

The argument has several variations, but it usually points out that in order for life to exist, a large number of physical constants must be within extremely narrow ranges. This is true. Given a random distribution of values, the likelihood of our universe having exactly the constants that it does is infinitesimally small. It appears as though it was made for life.

However, even within this exquisitely fine-tuned universe, 99.99999???% of it is uninhabitable. Most of it is vast emptiness. We are aware of billions of stars and an increasingly large number of planetary systems that don’t support life. Even on our own planet, in this tiny corner of the universe, the conditions for life are limiting. Life doesn’t thrive on earth’s deserts, from Sahara to Antarctica, and beyond certain temperature extremes. If you increase your altitude to just 10 miles — thinner than the paint on a desktop globe — you would not be able to survive for a prolonged period of time due to the low temperature and lack of oxygen.

When viewed in that light, the universe doesn’t appear well suited to life. Life struggles to survive in an exceptionally narrow range of this supposedly fine-tuned universe.

Further, I don’t see how anyone could argue that biological systems are well-designed. There are thousands of known hereditary diseases, which means there are thousands of ways for the human body to fail. We spend more as a percentage of GDP on medicine — the organized effort to control organic design failure — than just about anything else. And that doesn’t include all the environmental insults and communicable diseases (as if the innate design of the body wasn’t bad enough, God had to throw in thousands of other hurdles to thwart our ability to live, right?).

No, livings things do not exhibit good design. They exhibit a patchwork of good and bad designs, struggling against each other to survive — which is exactly what we would expect from a system that builds complexity through selection pressures on random modifications and historical constraints.

Every engineer knows that good design involves compartmentalization of subsystems, so if one part of the system fails, the whole system doesn’t have to fail. Yet what we see in living things is pleiotropy — parts get reused in many places, and the various subsystems constitute overlapping networks (that’s why drugs have side-effects). That’s bad design!

And why would a god produce a Creation that was innately pitted against itself? Predator against prey, parasite against host. It’s certainly not a harmonious existence. On the other hand, ecosystem dynamics are perfectly in accordance with what we would expect from evolutionary agents sampling the behavior space for local fitness maximization.

Finally, what about those constants? Why are they so fine-tuned? We don’t know. One hypothesis holds that we live in a multiverse, and that each universe takes on different values for those constants. Some are capable of supporting self-organizing chemistry (which is all that life is, at bottom), and some are not. Naturally, we would only end up in one that does, and we would marvel at how exquisitely designed it was “just for us.”

We have no evidence for the multiverse explanation, but then, we have no evidence for the existence of gods either. Without evidence to arbitrate between these explanations, they are equally likely. So you can’t claim that fine-tuning of the physical constants is ipso facto evidence of gods. I provided one alternative explanation, but there could be many more. Our inability to formulate better answers doesn’t make the ones that we have correct.

And it seems to me that the explanation involving a Supernatural Man, especially a Supernatural Man with all the character flaws of earthly humans, including jealousy and anger and vindictiveness, isn’t the best explanation we can come with. It’s the kind of explanation we would expect from primitive people who couldn’t think beyond their own psychosocial paradigm.

We can do better than to commit a Mind Projection Fallacy in order to explain the universe. The Argument from Design is insufficient.

Recently, I came across a believer who offered a unique argument for the existence of God. He had been reading about the beam splitter experiments that confirm quantum entanglement. Specifically, he had read about the delayed-choice quantum eraser, where they don’t “observe” the system until some time after the experiment, and the nature of the pattern on the detector (whether it’s an interference pattern or a solid pattern) changes, and future events appear to shape the past.

He argued that since the wavefunction can’t collapse — and quantum events can’t be determined — until after they are observed, then the universe couldn’t exist until there were observers. Since it obviously did exist, that means there must have been a Great Observer — God — long before there were conscious beings.

While interesting, this argument fails for two reasons. First, there’s nothing inherently special about observation. When you observe a system, even a quantum system, you are physically interacting with it, and it’s the physical interaction that changes the quantum state, ie, causes the wavefunction to collapse (Cf. environmental decoherence). Second, the wavefunction is holistic. It exists through all space and all time, so it already “knows” (if you’ll excuse the anthropomorphism) that the system will be “observed” at a later time. It doesn’t matter whether you do it tomorrow or a million years from now.

What do I mean that all of time exists? All of time exists now? If you ask that question, you’re still stuck in an intuitive way of thinking about time. All of time doesn’t exist now any more than all of space exists here. All of space exists, and all of time exists. That’s it. If you move in relation to a distant object, you move into its past or future time slices — into past or future “nows” for that distant object. They all exist concurrently. It’s a weird way of looking at the universe, but the universe behaves in weird ways. Our evolved psychological intuitions are adapted to the meso-scale environment that our ancestors had to negotiate for thousands of years. Saying that the universe is weird is really more a statement about us than the universe.

So while it was a good try, it was based on a lack of understanding of the underlying physics. But at least he was trying to learn something, and I appreciate his effort.

Most of the Email P.Z. received appeared to be well reasoned. I didn’t see any crazy death threats. It is what I expected to see.

Since Phil is a Catholic, he may have a valid point. You see, the substance of the letters was indeed reasonable. The parts of the letters which we could read were only the appearances, which are visible to the senses. Those may have seemed irrational, overblown, hysterical, histrionic, violent, or puerile, true — but only to the eyes of the world. And the worldly.

What they were in themselves, the underlying reality, was well reasoned.

It’s another miracle!

Written by Sastra. I wonder if that’s the same Sastra who frequents DALnet.

The myth of transubstantiation is based on an Aristotelian/Thomist view of the world, that there is some underlying substance or essence that permeates an object, and which may not or cannot be observed, and in consequence, empirically validated. The waveparticles that constitute the wafer are detectable and will continue to reveal a processed wheat product, but the essence changes into the body of Christ. You can’t demonstrate it empirically, you just have to take the Church’s word for it.

Of course, Aristotelian physics is nonsense because it can’t be validated in any reasonable way. How do you validate something that can’t be observed in principle? Evidence is the causal connection between our beliefs and reality, and we have no reason to believe something for which evidence does not or cannot exist.

To this day many people believe that consciousness is something special. It doesn’t fit within the natural world. It’s mysterious to us, therefore it must have a mysterious source. It seems that everything is magical to ignorant people.

Our forebears believed that an elan vital, a vital force, distinguished living things from nonliving things. It infused the corporeal body and animated it. Then we uncovered the biochemistry that produces life: metabolism, muscle fibers, actin and myosin, ATP, and so on. The explanation turned out to be completely naturalistic. The vital force had to die.

There are groups of people in the South Pacific who practice what’s called a cargo cult. When Americans arrived in the Pacific theater during World War II, they built landing strips and flew in planes with cargo. The natives were very much impressed with the wonderful goods that the magical steel birds were bringing. They concluded that their ancestors were sending the planes (the natives practice ancestor worship, a form of religion that predates the three “great” monotheisms). They started building their own landing strips and effigies of planes made from bamboo. They performed rituals, and waited, and waited, and waited. To this day they are waiting for the cargo to come.

Of course, the cargo will never arrive, because the natives are ignorant of the civilization and technology necessary to make airplanes that fly cargo. There is a completely naturalistic explanation to cargo planes.

The history of knowledge has one ineluctible pattern: every explanation that we have uncovered has been a naturalistic one. Why do people expect consciousness to be any different? It’s a difficult problem, but we are making headway. With better brain scanning technology and data mining / pattern recognition algorithms, we will unravel the problem of consciousness, and it will no longer be mysterious.

In my last post I pointed out that evidence gleaned from experiments must be used to arbitrate between the possible explanations of an observation. But what constitutes evidence?

A proper experiment changes one variable in the system, and valid evidence is the observation of the final state of the system after an experiment is performed. If there is no change between the initial and final states, that counts as evidence against a particular hypothesis. If there is a change in an expected manner[1], that counts as evidence for a particular hypothesis.

In the car example that I used before, we have a number of hypotheses for why the car won’t start: it may be the alternator, the spark plugs, or the battery. We replace the alternator and the car still won’t start. The initial and final states are unchanged. That’s evidence against the alternator hypothesis. We replace the spark plugs and the car won’t start. The spark plug hypothesis is ruled out. We replace the battery and the car starts. There was a change between the initial and final states of the system. We have evidence that confirms the battery hypothesis.

But what kind of experiment can we perform to test the God hypothesis? In each of the other experiments, we had to physically interact with something in order to confirm or disconfirm a hypothesis. That physical interaction was the causal connection between the object of the hypothesis and the state of the system. How do we interact with God, or with something else, to make a causal link between God and the system? What do we interact with to perform the experiment?

We are stuck at the starting line. Judging by the variety of religions and spiritual traditions in the world, there is considerable confusion over what the nature of God is and how to interact with Him. God is a poorly defined concept because there are so many definitions. We have a clear and concise concept of a battery, which means we have a clear way to test the battery hypothesis. We don’t have this luxury with the God hypothesis.

There’s a crucial point to be made here. Evidence is a hypothesis-killer. Without evidence, you can invent hypotheses endlessly, but once you acquire evidence, you start ruling them out. It is the only way to arbitrate among them. We have a clear definition of a battery because we have evidence of batteries. We can observe them. We can build them. But we have innumerable concepts of / hypotheses about God precisely because we lack evidence to arbitrate between them.

If you understand Bayesian reasoning, you understand why this does not bode well for the God hypothesis. Right now the God hypothesis is hopelessly muddled and lacks any means of testability, and this situation doesn’t look like it’s going to be resolved soon. Therefore, we are justified in rejecting the God hypothesis, at least for now.

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[1] The change must be of an expected manner. If we change the battery and the car explodes, there was a change between the initial and final states, but we can’t conclude that the battery was the cause of the car’s inability to start.